The invention relates to naphthylamino groups containing 1, 3, 5-triazine derivatives and their use particularly as stabilizing agents for elastomer compositions.
Elastomer vulcanizates undergo structural changes with increasing lifetime which result in an impairment of their use. The changes are caused by the action of oxygen, ozone, light and heat, either singly or in combination of these actions. If there is simultaneously a dynamic stress on the elastomer-vulcanizate the deleterious action is further increased. A number of materials have become known which are used to stabilize the elastomers against these deleterious effects. They are usually called antioxidants and may also be called antiageing agents.
While normal arylamines for instance .alpha.-or .beta.-naphthylamines do not have any antiageing effects or have only a very faint activity in this direction it is known that by substituting a phenyl ring for a hydrogen atom of a naphthylamine the highly effective antioxidants phenyl-.alpha.-naphthylamine (= PAN) and phenyl-.beta.-naphthylamine (= PBN) are obtained. However, these compounds have the shortcoming that they result in a strong discoloration of white or light colored elastomer vulcanizates under the action of light. In case of carbon black containing mixtures the formation of discoloring compositions results in color transfers which reduce the usefulness of the compositions wherever the vulcanizates come into contact with bright or light-colored materials, for instance paper, synthetic plastics or coating materials such as lacquers. These color transfers upon contact are well known and dreaded in the automotive industry.
1, 3, 5-TRIAZINE DERIVATIVES OF VARIOUS KINDS HAVE BEEN USED FOR VARIOUS PURPOSES. For instance these triazine derivatives are used with 2-, 4-, and/or 6-position halogen atoms and sulfur and/or nitrogen-containing substituents. It has also been proposed to use these materials as stabilizers for organic substances such as polymers (U.S. Pat. Nos. 3,240,749, 3,245,992, 3,257,354, 3,418,272, 3,530,127, British Patent No. 977,589, French Patent No. 675,785, etc.).
For instance in U.S. Pat. No. 3,257,354 it has been proposed to protect natural rubber or synthetic rubber such as cis-polyisoprene or a styrene-butadiene elastomer against oxidative degradation with such triazine compounds as are obtained from derivatives containing phenyl groups with free OH groups. The activity of these compounds is clearly based only on the presence of free phenol groups.
Other triazine derivatives are for instance disclosed in German published applications Nos. 1,240,083 and 1,241,452 for use as protection of organic materials against ultraviolet radiation. These compounds however likewise contain phenyl substituents with free OH groups.
The above-mentioned French patent discloses numerous derivatives of the s-triazines since the triazine ring can be substituted by a large number of substituents not further defined therein. These substituents can be attached either directly to the triazine ring or via hetero atoms such as oxygen, nitrogen or sulfur. Among these compounds are many triazine derivatives which have no antioxidant effect at all in elastomer vulcanizates. The few compounds specifically mentioned in the exampls of the French patent do not afford any mentionable age protection in vulcanizates as has been determined by test results. There is furthermore not indicated in the French patent any rule by which effective antioxidants or age protectors can be determined among the numerous and highly different triazine derivatives.
It could accordingly not be foreseen which particular 1, 3, 5-triazine derivatives would have valuable and superior properties for the elastomer vulcanization. The present inventors have found that, surprisingly, among the very large number of triazine derivatives there is a group of such derivatives which are highly effective anti-oxidants and have other valuable properties for the elastomer vulcanization.